What is a card security code?

A card security code (also called CVD, CVV, or CID) is a small number printed on your credit card that assures us that you have your card in hand. We never store this code on our servers, and you should never give it out to someone you do not trust.

Where do I find this code?

If you have a MasterCard, Visa, or Discover card, you can find it printed on
the signature strip on the back of your card. You only need the last three
digits.

If you have an American Express card, you can find it printed on the front of
your card, right above your card number. It is four digits long.